JP2002348497A - Radiation curable ink and print obtainable by using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radiation curable ink which has good receiving properties for a thermal transfer ink as a receiving layer, which brings about no blurs in thermal transfer printing and which can form the receiving layer having the good receiving properties in common to the equipment of the both firms of Rimage Company and Primera Company. SOLUTION: The ink is formed by dissolving an acrylic resin (a polymer or a copolymer containing an acrylate or a methacrylate) having a glass transition temperature (Tg) of 25-80 deg.C in a polymerizable monomer. By using a monomer containing ether bonds as a monofunctional monomer, the warp of the base material (CD, compact disc) becomes smaller to lead to good thermal transfer printing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-curable ink and a printed material using the ink as a receiving layer for printing.

[0002]

2. Description of the Related Art In recent years, thermal transfer printing has been performed on a label surface of an optical recording medium disk such as a compact disk. A typical example of a thermal transfer printing apparatus is R
image printing machine (Prims Printe)
r), a printing machine manufactured by Primera (Inscript)
a), each having a different device mechanism and a unique thermal transfer ink ribbon. However, CD-R and CD
-The thermal transfer ink did not directly adhere to the label surface of an optical recording medium disk such as a ROM (hereinafter collectively referred to as a CD), and direct printing was impossible. To solve this difficulty, for example, a special radiation-curable ink is printed and cured on the label surface of a CD to form a heat transfer printable receiving layer.

[0003]

However, conventional radiation-curable inks for forming a receiving layer are not satisfactory, and the receiving layer formed thereby has the following disadvantages.

That is, with the conventional radiation-curable inks, (1) the receptivity of the thermal transfer ink in the receiving layer is not sufficient, causing blurring of thermal transfer printing. (2) Particularly, Rimag
e, a receiving layer having good receptivity common to the devices of both companies, Primera, is not obtained, and there is a drawback such that a good device of one company cannot print at all with a device of the other company, (3) Defects such as warpage of the CD disk when the radiation-curable ink is cured, and (4) Blocking of the receiving layer and the plastic film when the product having the receiving layer is wrapped with a plastic film or the like. was there.

Accordingly, an object of the present invention is to provide a radiation-curable ink capable of forming a thermal transfer receiving layer without the disadvantages of the conventional thermal transfer printing receiving layer, and furthermore, it is difficult to perform thermal transfer printing. An object of the present invention is to provide a printing material in which a good printing receiving layer such as thermal transfer printing is provided on a transparent material.

[0006]

The above object of the present invention is achieved by a radiation-curable ink obtained by dissolving an acrylic resin having a glass transition point (Tg) of 25 ° C. to 80 ° C. in a polymerizable monomer. More preferably, the problem is solved more preferably by a radiation-curable ink obtained by dissolving an acrylic resin having a glass transition point (Tg) of 30 to 70 ° C. in a polymerizable monomer.

The acrylic resin used in the present invention is a polymer or copolymer containing an acrylate or a methacrylate. As an example, Mitsubishi Rayon Co., Ltd. brand name Dianal BR-105 (T
g = 50 ° C.), BR-106 (Tg = 50 ° C.), BR-
90 (Tg = 65 ° C.), BR-117 (Tg = 35
° C), BR-113 (Tg = 75 ° C), and Rohm and Haas Japan's trade name Paraloid B-38.
(Tg = 50 ° C.), B-82 (Tg = 35 ° C.), B-6
6 (Tg = 50 ° C.), B-67 (Tg = 50 ° C.), B-
72 (Tg = 40 ° C.) and B-60 (Tg = 75 ° C.).

The polymerizable monomer used in the present invention is a polymerizable monomer capable of dissolving the acrylic resin at room temperature. Examples include N-vinyl pyrrolidone, 2-ethylhexyl carbitol acrylate, phenoxy polyethylene glycol acrylate,
Monofunctional monomers such as phenoxyethyl acrylate and ethoxydiethylene glycol acrylate, and 1,6
And polyfunctional monomers such as hexanediol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, polyethylene glycol diacrylate, and pentaerythritol acrylate. Also, a mixture of these monomers or other monomers can be used.

When a monomer containing an ether bond is used as the monofunctional monomer, the warpage of the substrate (CD) is further reduced, and the thermal transfer printability is improved.

The glass transition point (Tg) of the acrylic resin of the present invention needs to be 25 ° C. to 80 ° C., and a more preferable range of Tg is 30 ° C. to 70 ° C. If the Tg exceeds 80 ° C., the thermal transfer ink may be fuzzy or, in extreme cases, may not be transferred at all. Further, the warpage of the substrate (CD) tends to increase. Also, Tg
Is less than 25 ° C., there is a disadvantage that tackiness occurs in the obtained receiving layer.

It is preferable that the resin amount is 10 to 50 parts by weight based on 100 parts by weight of the total amount of the acrylic resin and the polymerizable monomer.

The total amount of the acrylic resin and the polymerizable monomer is 1
If the acrylic resin is less than 10 parts by weight of the 00 parts by weight, the adhesiveness between the obtained receiving layer and the substrate (CD) is deteriorated, and the thermal transferability is also deteriorated. On the other hand, when the amount of the acrylic resin exceeds 50 parts by weight, the viscosity of the ink increases, and it becomes difficult to print the ink on the substrate (CD). If the polyfunctional monomer exceeds 50 parts by weight of 100 parts by weight of the polymerizable monomer, warpage of the substrate (CD) occurs at the time of forming the receiving layer, and the thermal transfer printability to the receiving layer also deteriorates. Monofunctional monomer in 5 parts by weight of monomer
Desirably, the amount is 0 to 100 parts by weight.

Further, the ink of the present invention may contain a polymerizable oligomer. Examples of polymerizable oligomers are polyurethane diacrylate, polyester diacrylate,
And polyether diacrylate. Further, it is preferable to add about 3 to 20 parts by weight in 100 parts by weight of the radiation-curable ink.

It is preferable that the solid filler is contained in an amount of 10 to 70 parts by weight based on 100 parts by weight of the radiation-curable ink of the present invention. When the solid filler is contained in an amount of 10 to 70 parts by weight, the tack of the receiving layer is reduced. However, when the solid filler is included in an amount exceeding 70 parts by weight, the thermal transfer printability is deteriorated, and the adhesion between the base material and the receiving layer is reduced. Gets worse.

As the solid filler of the present invention, silica,
Illustrate commonly known fillers such as talc, clay, zeolite, calcium carbonate, calcium silicate, magnesium carbonate, barium sulfate, mica, synthetic mica, diatomaceous earth, aluminum hydroxide, alumina, titanium oxide, powdered cellulose, powdered protein and the like. Can be. Among these, particularly preferred examples from the viewpoint of improving ink receptivity, blocking resistance, whiteness, etc. include silica, synthetic mica, aluminum hydroxide, alumina, talc, clay, calcium carbonate, and titanium oxide. Can be. These fillers are generally referred to as extenders, but may include general coloring pigments. The average particle size of the solid filler used in the present invention is preferably 0.1 to 30 μm, and more preferably 0.1 to 30 μm.
2 to 15 μm.

In the present invention, an electron beam, a γ-ray, an ultraviolet ray, a visible light, or the like can be used as radiation for promoting the polymerization of the monomer. UV rays as radiation,
When using visible light or the like, a photopolymerization initiator for initiating polymerization is generally used in combination. Therefore, the radiation-curable ink according to another configuration of the present invention further comprises a photopolymerization initiator.

Examples of the photopolymerization initiator are not particularly limited as long as radicals or other active species generated by light react with a polymerizable double bond in a monomer to induce a polymerization reaction. Examples include benzoin ethyl ether, 2-
Hydroxy-2-methyl-1-phenylpropane-1-
On, 1-hydroxycyclohexyl phenyl ketone,
2-methyl-1- (4- (methylthio) phenyl) -2
-Morpholinopropanone-1, bisacylphosphine oxide and the like. These photopolymerization initiators can be used alone or in combination of two or more. The use amount of these photopolymerization initiators is not particularly limited, but is generally about 1 to 10% by weight, preferably about 2 to 5% by weight.

Further, the ink of the present invention may contain a leveling agent, an antifoaming agent, a dye, a pigment and the like, if necessary.

The ink of the present invention can be printed by any printing method such as gravure printing, flexographic printing, and screen printing. However, in order to give the printing layer sufficient receiving performance, the thickness of the printing layer is preferably 1 to 1. It is desirable that the thickness be about 100 μm, more preferably about 3 to 40 μm.

Therefore, the most preferable example is screen printing in which the thickness of the printing layer can be easily adjusted to the above range. Further, the ink of the present invention can be used after being coated by a coating method.

In any case, the ink of the present invention can be cured in a short time by irradiating radiation such as electron beam or γ-ray or light acting on a photopolymerization initiator after printing or coating. Printing layer is provided.

The printing layer thus obtained is rich in receptivity and provides a preferable receiving layer. In addition, this receiving layer can be easily formed not only on paper but also on a base material such as a plastic film, a plastic plate, or a metal plate.

The receiving layer formed by the ink of the present invention contributes to improving the printability of the substrate. In other words, when printing is performed on the receiving layer by a method such as thermal transfer printing, the printed ink is promptly and reliably received by the receiving layer.
In these printings, the fixing property of the ink and the clarity of the printing result can be ensured.

The present invention also includes a printed matter obtained by printing and curing the radiation-curable ink on a substrate to form a printing receiving layer such as thermal transfer printing.

[0025]

EXAMPLES Examples 1 to 4 The compositions shown in Table 1 were kneaded to prepare ultraviolet curable inks. Each ink was screen-printed on the protective layer of CD-R (label side) and immediately irradiated with ultraviolet rays (1000 mJ /
cm ² ) and cured to form a receiving layer having a thickness of 10 μm. In Table 1, Tg of acrylic resin (B-82) =
35 ° C., Tg of acrylic resin (B-60) = 75 ° C., Tg of acrylic resin (B-38) = 50 ° C. The monomer A is N-vinylpyrrolidone, the monomer B is phenoxyethyl acrylate, and the monomer C is 1,6-hexanediol diacrylate.

Table 2 shows the performance of the ink comprising the obtained composition, where R is a thermal transfer printing machine manufactured by Rimage.
P shows the result of visually determining the degree of print goodness by a thermal transfer printing machine manufactured by Primera. ◎ means particularly good, 〇 means good, △ means not very good, × means bad.

The propylene film has a blocking property of 1
The propylene film was peeled off after 150 hours by pressing with kg / cm ² , and the tackiness at that time was evaluated. ◎ means particularly good, 〇 means good, △ means not very good, × means bad.

The method of measuring the warpage is as follows. First,
PET film (Melinex 705, trade name, manufactured by Teijin Dupont Film Co., Ltd.) with T-350 mesh
A cm × 12 cm peta print is made, and a test piece is cut out while leaving the outer periphery of the printed portion at 5 mm. The printed portion is cut diagonally with a cutter knife and left in an atmosphere of 50 ° C. and 98% humidity. After 150 hours, the water was lightly wiped off and allowed to stand for 1 hour, and then the magnitude of the warpage was determined based on the warped-up state of the vertices of the triangle formed by cutting the PET film (the vertices formed by the cut crosses). Those with no warpage were evaluated as ◎, those with warpage of up to 5 mm were evaluated as ○, those with up to 15 mm as Δ, and those with 15 mm or more as x. It has been separately confirmed that the determination of the warpage by this method has a correlation with the warpage of the CD when the receiving layer is printed on the CD.

[0029]

[Table 1]

[0030]

[Table 2]

Comparative Examples 1-2 Compositions having the compositions shown in Table 3 were kneaded to prepare ultraviolet curable inks. Each ink was screen-printed on the protective layer of CD-R (label side) and immediately irradiated with ultraviolet light (1
000 mJ / cm ² ) and cured to form a 10 μm thick receiving layer.

The same test as in the above example was conducted for the performance of the ink obtained from the composition, and the results are shown in Table 4. In Table 4, Tg of acrylic resin (trade name: Dianal BR-102) manufactured by Mitsubishi Rayon Co., Ltd.
= 20 ° C., Tg = 10 of acrylic resin (trade name: Paraloid A-11) manufactured by Rohm and Haas Japan
0 ° C.

[0033]

[Table 3]

[0034]

[Table 4]

As can be seen by comparing Tables 1 and 2 with Tables 3 and 4, the radiation curability of the comparative example obtained using an acrylic resin whose Tg is out of the range of the present invention even for the same acrylic resin. From ink, Rimage, Prim
A good receptive receiving layer cannot be formed in common with the devices of the two companies era and the substrate (CD disk) warps when the radiation-curable ink outside the scope of the present invention is cured. When the product having the receiving layer obtained from the radiation-curable ink outside the scope of the present invention is packaged with a plastic film or the like, the receiving layer and the plastic film are blocked.

On the other hand, the radiation-curable inks of the examples obtained by using the acrylic resin within the scope of the present invention are better than those of the comparative examples in the apparatuses of both Rimage and Primera. When the radiation-curable ink is cured, the substrate (CD disk) is not warped when the radiation-curable ink is cured. The plastic film does not block.

[0037]

According to the present invention, (1) the receptivity of the thermal transfer ink of the receiving layer is good, and there is no blurring in thermal transfer printing.
(2) In particular, it is possible to form a receiving layer having good receptivity in common with the devices of both Rimage and Primera, and (3) warp of the substrate (CD disk) when the radiation-curable ink is cured. And (4) a radiation-curable ink capable of forming a receiving layer in which the receiving layer and the plastic film do not block when the product having the receiving layer formed thereon is wrapped with a plastic film or the like. Further, by using the radiation-curable ink of the present invention, it is possible to provide a printing material provided with a printing-friendly receiving layer such as thermal transfer printing on a material that is difficult to thermally transfer print.

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[Procedure amendment]

[Submission Date] June 5, 2001 (2001.6.5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction contents]

COMPARATIVE EXAMPLES 1 AND 2 A composition having the composition shown in Table 3 was kneaded to prepare an ultraviolet curable ink. Each ink was screen-printed on the protective layer (label surface) of the CD-R and immediately irradiated with ultraviolet rays (1000 mJ / cm ² ) to be cured to form a 10 μm-thick receiving layer. Table 3
Acrylic resin manufactured by Mitsubishi Rayon Co., Ltd.
Ianal BR-102) Tg = 20 ° C, ROHM A
Acrylic resin (trade name PA
The Tg of Laloid A-11) is 100 ° C.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0032

[Correction method] Change

[Correction contents]

[0032]

[Table 3]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction contents]

The same test as in the above example was conducted for the performance of the ink comprising the obtained composition, and the results are shown in Table 4.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H111 CA03 CA25 CA30 4J038 BA022 BA182 CG002 FA011 FA111 FA241 HA216 HA246 HA266 HA446 HA456 HA506 KA08 KA20 MA09 MA13 NA10 NA12 NA17 PA17 PB14 PC06 PC08

Claims (6)

[Claims] 1. A glass transition point (Tg) of 25 ° C. to 80 ° C.
A radiation-curable ink obtained by dissolving an acrylic resin as described above in a polymerizable monomer. 2. The radiation-curable ink according to claim 1, wherein the resin amount is 10 to 50 parts by weight based on 100 parts by weight of the total amount of the acrylic resin and the polymerizable monomer. 3. The radiation-curable ink according to claim 1, wherein the monofunctional monomer is 50 to 100 parts by weight based on 100 parts by weight of the polymerizable monomer. 4. The radiation-curable ink according to claim 3, wherein 50 to 100 parts by weight of the monofunctional monomer is a monomer containing an ether bond. 5. The radiation-curable ink according to claim 1, wherein a solid filler is contained in an amount of 10 to 70 parts by weight based on 100 parts by weight of the radiation-curable ink. 6. A printed matter obtained by printing and curing the radiation-curable ink according to claim 1 on a substrate to form a printing receiving layer such as thermal transfer printing.